1. Field of the Invention
The present invention relates to a metal treating method, and more particularly to a metal treating method of melting, on the periphery of the weld, a metallic plate partially welded on a metallic member and demounting the metallic plate from the metallic member, an to and apparatus for performing the method.
2. Description of the Prior Art
In the repair the sheet metal of a vehicle, the sheet metal, which is spot-welded at many portions, is required to be demounted from the vehicle. As a method of demounting the spot-welded metallic plates of this type, it was the conventional method to vertically depress a drill against the weld of the metallic plate and lower the drill, while rotating the drill by a motor, to sink it to a required depth. This method required the drilling of a center hole, or centering. Also, as the weld increased in hardness due to the thermal influences during the welding operation, a substantial drill depressing force was required for sheet metal removal so that the lower plate was often damaged, thus requiring labor and skill to be performed correctly. In addition, the consumption of the edge tool was large, resulting in high cost.